Thermoelectric materials or devices are those that convert energy from heat into an electrical potential when a temperature gradient is induced between the two ends of a material.
As heat is a by-product in many modern scenarios, the range of application to generate additional thermoelectric energy is vast. This includes industries such as:
- Textile (i.e. wearable electronics)
- Power generation.
However, current thermoelectric devices are composed of semiconductor materials which tend to be toxic, inorganic and expensive to manufacture.
In our current project, carbon nanotubes are shown to be an effective alternative thermoelectric material with properties that include mechanical flexibility, low manufacturing cost and non-toxicity. A common technique used to functionalise carbon nanotubes while doping to exhibit n-type and p-type semiconducting properties, is typically achieved by introducing chemical compounds such as polyethylenimine.
A high figure of merit for thermoelectric devices (i.e. efficiency rating) requires a high Seebeck coefficient, high electrical conductivity and a low thermal conductivity. We measure these parameters within a custom made thermoelectric analysis device, which features a vacuum controlled chamber, with a remotely controlled heating element and active cooling system, providing the necessary high temperature gradients. This set-up allows us to explore thermal conductivity and thermoelectric properties of next generation flexible thin film materials, such as carbon nanotubes and other carbon based materials.
Photoluminescence Quenching in Carbon Nanotube-Polymer/Fullerene Films: Carbon Nanotubes as Exciton Dissociation Centres in Organic Photovoltaics
N. Aamina Nismy, K. D. G. Imalka Jayawardena, A. A. Damitha T. Adikaari and S. Ravi P. Silva.